A study of fracture behaviour of gamma lamella using the notched TiAl micro-cantilever. Issue 8 (17th April 2020)

• Record Type: Journal Article
• Authors: Ding, Rengen; Chiu, Yulung; Chu, Mingqiang; Paddea, Sanjooram; Su, Guanqiao
• Is Part Of: Philosophical magazine. Volume 100:Issue 8(2020)
• Page Start: 982
• Page End: 997
• Publication Date: 2020-04-17
• Subjects: Fracture -- FIB -- Electron microscopy -- γ-TiAl -- Microcantilever; Condensed matter -- Periodicals; Physics -- Periodicals; Matière condensée -- Périodiques; Physique -- Périodiques; 530.41
• DOI: 10.1080/14786435.2020.1714088
• Languages: English
• ISSNs: 1478-6435

Abstract

ABSTRACT: Microcantilevers were machined from a single γ(TiAl)-α2 (Ti3 Al) lamellae colony of a polycrystalline commercial Ti-45Al-2Mn-2Nb sample using the focussed ion beam. The long axis of the microcantilevers is perpendicular to the lamellar interface with the notch prepared in the same γ lamella. Bending test results demonstrated good repeatability and the fracture stress intensity factor of individual γ lamella was measured to be 3.1 ± 0.2 MPa m 1/2 . ( 1 ¯ 1 ¯ 1 ) [ 1 ¯ 1 ¯ 2 ¯ ] twinning ahead of the notch (crack) tip plays a key role in the crack initiation. TEM analysis shows that the interaction of twinning with the lamellar interface leads to interfacial cracking and contributes to the work-hardening observed.